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[Towertalk] 15M on C31XR

To: <towertalk@contesting.com>
Subject: [Towertalk] 15M on C31XR
From: ve9aa@nbnet.nb.ca (Mike & Coreen Smith)
Date: Wed, 8 May 2002 03:32:22 -0300
The Nerve! Posting something actually reflector related!
(TIC)
;-))))

Subject: [Towertalk] 15M on C31XR


> Hello All
> 
> Since the talk about antennas and towers seems
> far and few between lately, I'm gonna throw
> something out for reflection. I've tried 
> asking this on the Force12 reflector a 
> couple years ago before but didn't get 
> much response. Since this antenna is even 
> more wide spread now, Steve suggested I
> try it over here.  (I also figure 
> ALL of them are over here plus more.)
> 
> ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~`
> 
> I have a C31XR. I'm quite happy with it but I 
> get the "feeling" 15M isn't playing as well as it
> could. Yes!, that's a really hard thing to quantify.
> 
> 1) The antenna's SWR on 15M reaches it's minimum 
> between 20.0MHz and  20.3MHz. I just use a tuner
> to make the rig happy. I know that SWR is not the 
> be all and end all but I know the expected minimum 
> SWR for the antenna design is higher up the band.
> 
> 2) After several years of competition, I just keep
> getting the heck beat out of me on 15M. (I feel
> competitive 10M and 20M.) When others in the area 
> have high Q totals on 15, mine are always mediocre. 
> I do accept the possibility that I may just be a lousy
> contester too.
> 
> No, this is not a case of adjusting the infamous 
> parallel wires, this antenna is feed with 3 separate
> feedlines (though I am tempted to go to one feedline
> just to see if things improve). I am well versed in 
> all the ONE feedline techniques but it's not the
> same beast.
> 
> Yes, I have made all the changes in the 
> instruction book (moved driven element back, different 
> hairpin coil, shortened and lengthned specified elements,
> etc). I have rechecked the measurements until I am blue
> in the face. I have made sure the tubing is going the
> right direction (an easy mistake if not careful).
> 
> Last summer, I had it down and played with the driven element
> length just to see if I could raise the frequency at
> which the SWR bottom out. (I realize I may have messed up
> my gain and f/b but it was an experiment). I got it
> where I wanted it at ground level (about 20') but as 
> soon as it went back up the tower - same result, back 
> into lower 20MHz region.
> 
> So, I am looking for someone else with the same antenna,
> feed with 3 feedlines, who may have experienced a similar
> situation and solved it. It's not intolerable, the antenna
> (at 100') works and it beats a C3S I have at 40' - it just
> doesn't seem up to par with the other bands. 
> 
> I thought I would throw it out and see what floats up. 
> Give us something to think about beside viruses and
> insurance. :>) (NO criticism intended on ANYBODY)
> 
> 73
> dink, n7wa
> 
> 
> 
> 
> 
> 
> 
> 
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